1. Field of the Invention
The present invention relates to bonded batt insulation useful for thermal or acoustic insulation. The insulating batt comprises secondary fiber and binder fiber bonded together. Bulking or lofting fiber can also be added to give additional volume to the insulating batt.
2. Description of Related Art
Loose fill secondary fiber insulation obtained from recycled paper has been in use for more than forty years. Such insulation is not bonded together and thus has no form or structure. A method to increase the bulk of secondary fiber loose fill insulation was disclosed in U.S. Pat. No. 4,468,336 wherein the addition of small amounts (2-8%) of synthetic fiber increased the bulk of the hammermill pulverized secondary fiber loose fill insulation. However, these advances did not lead to any form of bonded insulation.
Batt insulation can be made from a variety of materials such as fiber glass, rock wool, and textile materials. Processes for making a bonded insulating batt are described in Lewellin, U.S. Pat. No. 4,678,822 and Muncrief, U.S. Pat. No. 5,057,168. These processes use textile and binder fibers to form a batt using conventional textile carding and cross-lapping equipment. The resulting batt is then bonded.
A method for making a structured insulation material was developed by Horton and is disclosed in U.S. Pat. No. 4,804,695. Horton describes a method for producing spray cellulosic insulation and for wet spray open cavity insulation of such material. This method uses a composition which preferably comprises an adhesive and a wetting agent in water to moisten the material as it is blown into cavities. This process does not yield a product in batt form and it is necessary to transport the spray equipment to the job site. Furthermore, the density of these products is high.
None of the processes described above use secondary fiber as the insulating material, nor can secondary fibers be used in such processes.
With the continuing increase in energy costs, the need for a low cost, high performance insulation continues to grow. There is also a need to recycle secondary fiber such as newspapers so as to conserve natural resources. There is thus a need to provide a low cost, high performance insulation that can utilize secondary fiber. The product should also have a good recovery from compression, so that it regains most of its original bulk upon decompression.